Living to XS

A big torquey twin in a light and nimble chassis has always been a recipe for a good motorcycle, but it took a Japanese company and British developers to show the world how it should be done.

For such a large capacity machine the XS650 is physically quite small. The lithe and compact bike feels, and indeed looks, as if it was created out of leftover RD chassis and cycle parts with a big lump of a twin-cylinder four-stroke unit dropped in as an afterthought.

In reality this first impression isn’t so far away from the truth and the very early, pre-75, versions of the XS were exactly that; with a chassis and fork set up too thin and weedy to keep the plot running straight and true. With the B model things improved immensely enabling a fair impression of good handling to be carried off.

With a mere 50 odd horses on tap, and weighing more than a modern day sports bike, the ride is never going to be high spirited but it is fun from the off. The torquey, 360-degree engine, pulls from as low down as 1800rpm, all the way through to the 7500rpm redline. With a shade under 40ft-lb of torque on tap across a wide portion of the rev range the acceleration and pulling power is brisk no matter where you decide to unleash it. There is some vibration around the 4000rpm mark and then again up near the 6000rpm position, but this is simply the trade mark of an inline twin that has the pistons travelling up and down in unison, and difficult to eradicate without complex (and power sapping) balance shafts and counter weights. Yamaha chose not to go down that route with their first four-stroke design and let us have it just as nature had intended, warts and all.

Immediately the willingness of the engine makes itself apparent. A pair of constant vacuum Mikuni carburettors feed the fuel in with stunning precision, no matter when you open the taps, while a mechanical, advance and retard, unit keeps the sparks firing exactly where you want them to for the best performance throughout the rev range.

All round the XS is a delightful machine to be on. it is no more powerful than most 400cc machines of the day but it has its own way of doing things. Horsepower isn’t everything and torque plays an important part in the bikes make up, that constant thump propelling the bike along at all speed rather nicely.
If set up correctly, it will start at the slightest press of the button, and, will play all day if required. The small chassis is easy to move around and allied to the strong and dependable engine creates a superb ride. You can either dive up and down the gearbox in a mad rush to enjoy the higher end of its speed range or just leave it to plod along at a more sedate and relaxed pace. Either way the ride is always fun. Even two-up, the engine doesn’t appear to take too much notice of the extra weight and just keeps on pulling as before.

The seat is a shade on the thin side and is most probably the limiting factor in exactly how long you could spend in the saddle. The positioning of the footrests doesn’t help either, leading to an uncomfortable riding style with the rider sat almost upright. There simply isn’t enough foam between you and the bike to make the ride more comfortable. The lack of seat padding does give a better feel of what the bike is doing on the road however, and may have been another area that was altered to improve the original machines road holding.

What doesn’t help the rider control the bike is the excessively rubber mounted handlebars. These add a millimetre or two of slack into any input and it does take a little getting used to at first. Of course without the flexible bars the engine vibrations may well cause severe numbing of the hands with prolonged use.

As bikes go, the XS650 is a pretty basic design. It doesn’t challenge any of the Japanese multi-cylinder motorcycles from the same period in the technology stakes, but it did carve a niche for itself. There's something about the character of a big, lightweight vertical twin that evokes the passions of bikers everywhere. Coupled with the reliability that Yamaha brought to the party it's hardly surprising that the XS650 built such a strong and loyal following.


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